Hi,
I'm having the same problem as beatpete. I've pinged both computers, and they each see the other. The VEPro instances on my Mac (host) show up, but not the ones on my PC (server). The firewall on the Mac is turned off.
I've just bought a new MacPro (2019) running Catalina, but I made sure the IP specs on the new machine are the same as my old Mac. I'm running the latest version of VEPro 6 on both machines.
Any other ideas?